1. Field of Invention
This invention relates generally to document creation that allows for tracing the origin of the document and verifying the authenticity of a document.
2. Description of Related Art
It is often desirable to be able to trace the origin and to verify the authenticity of a document. Documents, such as currency, bearer bonds, and stock certificates, may be forged by scanning an image of the document and producing a copy of the document from the scanned image. Current methods available for tracing the origin of a document or verifying its authenticity include pseudo-random iridescent spots applied to the document during printing, and data glyphs or digital watermarks formed in the document during printing. These methods rely on the secrecy of the underlying encoding algorithm used to encode the identifying marks. If the encoding algorithm is decoded, a forger can create copies of the documents that are indistinguishable from the authentic documents. The use of an encoding algorithm to apply identifying marks to a document also increases the complexity of the printer software.
Other methods of tracing the origin of a document or verifying its authenticity include water marks, iridescent planchettes, luminescent inks and fibers, and chemical reagents applied to the paper. All of these methods, however, require the use of special paper or treatments for the paper which increase the cost of creating the document.